Some hardcore Amazon foes broke into a company-owned building in Long Island City, Queens, Saturday evening, scrawling “Scama­zon.con” across its floor-to-ceiling windows from the inside.

The graffiti, noted by cops at about 5 p.m., was washed from the windows overlooking the East River within three hours.

The 108th Precinct is investigating the break- in, according to sources.

It’s just the latest anti-Amazon graffiti to strike the neighborhood, where activists and politicians are opposing the retail ­giant’s plans to establish a second headquarters — with help from $2.8 billion in city and state tax grants.

Multiple “Amaz-NO” tags have been spray-painted on sidewalks and buildings.